1. Technical Field
The present invention relates to a display apparatus in which a bezel abutting a peripheral edge of one surface of a display panel and a chassis holding the display panel from the other surface side are fastened to each other by screws.
2. Description of Related Art
Display apparatuses such as a liquid crystal display and a liquid crystal television have been widely distributed. The display apparatus includes a display panel having a display surface for displaying an image on one surface. In addition, the display apparatus has often a configuration in which a bezel abutting a peripheral edge of the display surface from the one surface side of the display panel and a chassis holding the display panel from the other surface side are fastened to each other by screws to form a housing. Further, the display apparatus performs various types of signal processing during displaying an image on the display panel, and an electronic circuit for performing the various types of signal processing and a printed board on which the electronic circuit is mounted are appropriately disposed in the housing. The housing formed by the bezel and the chassis is often made of metal.
Recently, in the display apparatus, the number of pixels is increased depending on an increase in the size of a screen and enhancement of image quality, and the multifunctionality thereof such as a double-speed display or quad-speed display that displays an image by adding an interpolation frame between respective image frames has been progressed. Accordingly, signals that should be processed by the display apparatus are increased, and a processing speed of the signal processing by the display apparatus is accelerated. When the signal is transmitted at a high speed by wiring patterns formed on the printed board, harmonics are generated, which become a noise current to be leaked out from the printed board (wiring patterns). In addition, when the noise current has reached the bezel or the chassis, an electromagnetic wave noise is radiated to an outside of the display apparatus through the bezel or the chassis serving as an antenna. In this case, when a frequency of the electromagnetic wave noise and a resonance frequency of the bezel or the chassis coincide with each other, an amount of radiation of the electromagnetic wave noise is increased.
The electromagnetic wave noise radiated from the display apparatus (hereinafter, referred to as an electromagnetic interference (EMI)) may affect other surrounding electronic equipment or a human body, such that it is necessary to suppress the EMI. Therefore, in Japanese Patent Application Publication No. 2012-27203, a configuration in which washers having a lower electrical conductivity than the bezel and the chassis are interposed between the bezel or chassis and the screws has been proposed. In such the configuration, even when the noise current is conducted from the printed board to the bezel or the chassis and electromagnetic resonance occurs, a resonance energy is converted into a heat energy by the washers to be consumed, and thereby the EMI may be suppressed.